Mathematical model of coordination number of spherical packing

The article considers a mathematical model of the coordination number, which allows obtaining an equation for multi component spherical packing in the entire range of its change. The resulting model can be used in both 2-d and 3-d spaces. The concept of the coordination index is introduced as a function of the inter-particle distance related to a single particle located near the central particle. The model provides unambiguous compliance between the simulated and calculated data on the coordination numbers of the spherical packin

Astrophysical S17(0) factor extraction from breakup of 8B on 58Ni at energies near the Coulomb barrier

We have performed continuum-discretized coupled channels (CDCC) calculations of the breakup of 8B on 58Ni and direct proton transfer for the 8B+58Ni system at laboratory energies of 20-28.4 MeV. The influence of the 7Be core-target optical potential (OP) on the breakup cross section was investigated. Elastic scattering angular distributions for the 7Be+58Ni and 8B+58Ni systems at five different energies around the Coulomb barrier were studied, and a reasonable energy-independent OP for each system was obtained. Using these OPs and two different 7Be-p relative motion wave functions, and summing breakup and direct proton transfer contributions, we were able to fit the experimental cross section at a 8B laboratory energy of 25.75 MeV. We calculated the excitation function for the 7Be emission in the 8B+58Ni reaction, where 7Be products were measured at the forward angle θlab=45° in the energy interval Elab=20-28.4 MeV. In view of the peripheral character of the B8 breakup reaction at near-barrier energies, we could extract the asymptotic normalization coefficient for the 7Be-p system, which was found to be CBe-p,p3/22=0.543±0.027 fm-1. Finally, the astrophysical S17(0) factor was found to be S17(0)=20.8±1.1 eV b.Ministerio de Ciencia e Innovación FPA2006-13807-c02-01Programa Consolider-Ingenio 2010 CSD2007-0004

Possible Existence of Neutron-Proton Halo in 6Li

One of the most recent results was the determination of the proton halo in the first excited state of the 13N nucleus using of an analog of the MDM method for the charge exchange reactions (3He, t). It turned out that this state has the same radius as the mirror state 1/2+, 3.09 MeV in 13C.This observation allows us to take the next step and try to apply this approach to measure the radii of states. The increased radii in the isobar - analogue states of the 6He-6Li-6Be triplet, which may also have a halo structure, are not excluded. As a first step, we analyzed the published differential cross sections for inelastic scattering of 3He + 6Li with the excitation of the 2.19 MeV, 3+ state at energies 34 and 72 MeV and 3.56 MeV, 0+ state at energies 24.6 and 27 MeV. Probably the state 0+, 3.56 MeV has the same radius as its ”Borromian” isobar analogue 6He and is neutron-proton halo. The predicted enlarged radius because of the more extended wave function p - n, apparently, does not take place. We recall that the spatial structure of the 6He nucleus was predicted to be quite complex, in which correlations of two types appeared: ”cigar” and ”dineutron”. The question arises: does the structure of the state change so much when passing from 6He to the isobar-analoguein6Li,whichrequirestheintroductionofaspecialkindof“tango-halo”

Comorbid disease in children and adolescents with perinatal HIV infection: A pilot study

Background. With the increased use of combination antiretroviral therapy, the mortality of people living with HIV has decreased significantly, which has led to an increase of comorbidity and secondary HIV-related pathology in both adults and also in children and adolescents living with HIV infection. The incidence of children and adolescents with HIV infection and those in the general population varies significantly.The aim. To assess the frequency and range of chronic comorbidities in children and adolescents with perinatal HIV infection Methods. We carried out an observational study. Data on the incidence of 161 children with perinatal HIV infection registered in the Irkutsk Regional AIDS Center were copied.Results. Overall incidence of tuberculosis (18633.5 per 100 000 children), diseases of the digestive system (24844.7 per 100 000 children), diseases of the eye and adnexa (28571.4 per 100 000 children), diseases of the nervous system (18012.4 per 100 000 children), mental and behavioral disorders (13,664.6 per 100 000 children) in children with perinatal HIV infection is the higher than in children of comparable age. The overall incidence values of the endocrine system diseases, eating and metabolic disorders, diseases of the ear and mastoid process, diseases of the circulatory system, diseases of the genitourinary system, as well as congenital disorders and chromosomal disorders in children and adolescents with and without perinatal HIV infection are comparable.Conclusion. The prevalence of diseases of the circulatory, respiratory and genitourinary systems in children with perinatal HIV infection is comparable to that in the corresponding population. Prevalence of tuberculosis, anemia, diseases of the gastrointestinal tract, diseases of the eye and adnexa, diseases of the nervous system, mental and behavioral disorders is higher compared to children not exposed to HIV

Polymorphism T3111C of the Clock gene in ethnic groups of women from Russia and Buryatia

Biological rhythms of organisms depend on both changing conditions of the external environment and internal “biological clock”. Circadian rhythms are the response of the organism to the change of day and night. They are some of the most important biological rhythms of organisms. Circadian rhythms are regulated by the group of circadian genes. It is known that women suffer from sleep disorders more often than men. Up to 50 % of menopausal women complain of problems associated with sleeping. The study involved 403 menopausal women aged from 45 to 60 years: 214 Russians (the average age is 52.74±6.28 years) and 189 Buryats (the average age is 51.95±5.13 years) living in Eastern Siberia (Irkutsk region, Irkutsk and Republic of Buryatia, Ulan-Ude). The prevalence of genotypes and alleles of the polymorphism T3111C of the circadian rhythm gene Clock (rs1801260) was studied in these groups. To this end, we conducted genotyping of DNA samples by polymerase chain reaction. It was shown that the compared groups have statistically significant differences in genotypes frequency (р = 0.001). It was found that in the group of Russian women the frequency of the TC genotype (p = 0.004) was significantly higher and the frequency of the TT genotype (p = 0.0001) was significantly lower than those in the sample of women of Buryatia. It was shown that in the group of Russian women allele 3111C is found in 30.4 % of cases, which is statistically significantly more often than in the group of Buryat women, where the frequency of allele 3111C was 19.3 % (p = 0.014)

Sequencing of a fragment of the leptin gene in adolescents with different weight status

Background. Obesity is a significant social problem among the population of the world. The leptin gene (LEP) is currently considered as a potential candidate gene influencing metabolic disorders associated with predisposition to overweight and obesity. Leptin plays an important role in body weight homeostasis by influencing food intake and energy expenditure and maintaining constant energy stores. A defect in the leptin gene may be one of the causes of obesity and, as a result, of various obesity-associated pathologies. The aim of the study. To search for single-nucleotide polymorphisms (SNP) of the leptin gene in adolescents with different weight status. Methods. The study involved 20  adolescents aged 11–17  years with normal body weight and  overweight/obesity. Research methods: assessment of clinical status with  anthropometry; Sanger sequencing of the leptin gene fragment localized in the  intron of this gene – (5’-AGCCTTGTTTTCATCATCTGGA, 3’-TGGGAGGAATCGCTCTCAGA). We also carried out bioinformatic processing of sequencing results. Results. As a result of the study, the optimal conditions for amplification of the 891 bps leptin gene region were selected for the above mentioned primer pair of the LEP gene (s16_L891, s16_R891). Based on the results of sequencing, 45 single nucleotide substitutions of the LEP gene were identified, including 23 single nucleotide substitutions which were not previously registered in GenBank. In the group of adolescents with overweight and obesity, 14 unregistered single nucleotide substitutions of the LEP gene and 13 registered SNPs were identified in the GenBank database. In the group of adolescents with normal body weight, these SNPs were not found

Faraday rotation spectra of bismuth-substituted ferrite garnet films with in-plane magnetization

Single crystalline films of bismuth-substituted ferrite garnets have been synthesized by the liquid phase epitaxy method where GGG substrates are dipped into the flux. The growth parameters are controlled to obtain films with in-plane magnetization and virtually no domain activity, which makes them excellently suited for magnetooptic imaging. The Faraday rotation spectra were measured across the visible range of wavelengths. To interprete the spectra we present a simple model based on the existence of two optical transitions of diamagnetic character, one tetrahedral and one octahedral. We find excellent agreement between the model and our experimental results for photon energies between 1.77 and 2.53 eV, corresponding to wavelengths between 700 and 490 nm. It is shown that the Faraday rotation changes significantly with the amount of substituted gallium and bismuth. Furthermore, the experimental results suggest that the magnetooptic response changes linearly with the bismuth substitution.Comment: 15 pages, 6 figures, published in Phys. Rev.